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What fuel gauge SHOULD I have?

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George Zeck

George Zeck

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Hi All:

I'm dealing with a problem that I've not dealt with since 2003, successfully -- a working fuel gauge.

I have a 1964 AH Sprite MK II (HAN 7L 36045 Chassis #).

I have a BF2300 / 02 (recently found out it's from a 1964-67 MGB with a 12 gal tank). I have a ~ 7.5 gal.

I've read I should have a FG2530/54 or FG2530/70.

I've read, many times over the years, the how to adjust & calibrate a gauge and am totally uncomfortable with that. I feel my odds of success are low on that one, especially when starting with soemthing totally wrong (as I've found out).

I will replace sending unit as well at the same time (which I know is trashed).

Any resources to know which I should have - they aren't all the same.

Thanks-

George
 
The best source of fuel gauge information is on Barney's website:https://mgaguru.com/mgtech/electric/fg_01.htm
The early MGBs had a fuel gauge which I believe was similar to the Midget: i.e. used a sender with 0 ohms for empty and 90 ohms for full. The Midget Mk3 used a voltage stabilizer, which your car did not originally have. I do not have information if the 1964-1967 MGB gauge needed the stabilizer. All the MGBs and Midgets with voltage stabilizer had sending units with the opposite logic....with 0 ohms for full. I would try to find out if the fuel gauge you now have needed a voltage stabilizer. If it does, then it will not work with a sending unit which is correct for your car as the logic is opposite. Hope I didn't confuse you too much...good luck
Scott in CA
 
Scott gave you excellent advice. I only have a few things to add.

You need to measure the resistance range of the sender in your tank. As mentioned above, the non-stabilized gauge system will vary between about 0-90 Ohms, empty to full. The later bimetallic gauge system uses a sender that varies between 270 to 30 Ohms, empty to full. All those values are approximate, not exact. Once you know the sender's resistance range, turn your attention to the gauge. The later, stabilized gauges have broad, almost straight sided needles that have a point at their tip. The early, non-stabilized gauge have a more narrow needle that tapers from top to tip. The early non-stabilized gauges "snap" to position when you apply power. The later bimetallic gauges have needles that creep up to position because of slow internal warming.

You cannot mix components from the early and late gauge systems. There is a work around possible. Visit Spiyda Design's website and order their Gauge Wizard. Chris who runs the business made his Gauge Wizard to allow matching almost any sending unit with any gauge, including reversed acting ones.

Spiyda Design Gauge Wizard Link
 
If you don't like messing with electronics and the gauge is reading but not quite accurate you can adjust by bending the float arm, pretty easy to do
 
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